Biological Pests

Common insect pests: a guide to identification and non-toxic control

Beetles

Beetles make up the largest insect order. All have a complete life cycle. That is, they develop right through from larval stage to adults. They can be distinguished from other insects by their hardened wing-covers, which are called elytra.

Cigarette beetles

Description: Adults are 2–3mm in length, oval-shaped and brown to red in colour. Their hardened wing-covers are covered in fine hairs and their antennae are serrated. Larvae are cream to white-coloured and hairy.

Attack: They attack a wide variety of plant and animal-based materials. The destructive stage is the larval stage. But the adults often cause damage when they eat their way out of a food source: chewing their way out of a cereal box, for example. Affected materials will have a shot-hole appearance.

Cigarette beetle—Lasioderma Serricorne. Photograph courtesy of the Museum and Art Gallery of the Northern Territory

Control: Thoroughly inspect and treat new acquisitions as necessary to prevent their introduction. Locate, then have treated, the source of the infestation. Arrange for the treatment of any infested artefacts using one of the low-toxic methods available: freezing, low-oxygen and controlled atmospheres. Pheromone traps are available for cigarette beetles, and are useful in locating infested material.

Drugstore beetles

Description: Drugstore beetles are almost identical to Cigarette beetles in their size and feeding habits. The main difference is that Drugstore beetles have lines of pits on their hardened wing covers and their antennae end in a three-segmented club.

Attack: They attack a wide variety of plant and animal-based materials.

Control: Thoroughly inspect and treat new acquisitions as necessary to prevent their introduction. Locate the source of the infestation. Arrange for the treatment of any infested artefacts with one of the low-toxic methods available: freezing, low oxygen and controlled atmospheres.

Spider beetles

Description: Adults are 1.5–4.5mm in length, are red or brown-black in colour, with a bulbous body and long legs, and resemble small spiders. Their larvae are white and up to 4mm long, and often spin a silken case in which to feed.

Attack: Spider beetles attack a variety of plant and animal-based materials.

Control: Thoroughly inspect and treat new acquisitions as necessary to prevent their introduction. Locate the source of the infestation. Arrange for the treatment of any infested artefacts by one of the low-toxic methods available: freezing, low oxygen and controlled atmospheres.

Carpet beetles

Description: There are several species which will attack museum and library collections. The adults are up to 5mm in length and are oval or elongated oval in shape. They vary in colour, depending upon the species, and can be black, white, brown, mottled or variable. The larvae vary in size, depending on the species; they are very active, and usually brown in colour. All are covered with bristles. The only evidence usually found of this beetle's presence is cast-off skins of the larvae and pupae.

Carpet beetle - Attagenus Fascisculatus. Photograph courtesy of the Museum and Art Gallery of the Northern Territory

Carpet beetle larvae. Photograph courtesy of the Western Australian Museum

Attack: All damage is caused at the larval stage. The adults are mostly pollen or nectar feeders, which means that this pest could come in on cut flowers.

The materials likely to be attacked include wool, fur, hair, feathers, silk, insect specimens and other products of animal origin, for example, horn. They will also attack books, making irregular holes and cavities for pupation.

Control: Thorough vacuuming, with particular attention to areas which are rarely disturbed as these are often used for pupation. Avoid bringing cut flowers into storage areas. Thoroughly inspect and treat new acquisitions, to prevent their introduction. Locate the source of infestation. Arrange for the treatment of any infested artefacts by one of the low-toxic methods available: freezing, low-oxygen and controlled atmospheres.

Borers

Borers are insects which as larvae bore their way through timber. Most borer larvae feed on the sugars and starch found in the sapwood of trees. When the larval stage of their life cycle is complete, the adults emerge through holes which they make in the surface of the wood. The length of time taken for the life cycle depends on many things, including the temperature and moisture content of the wood. There are many different types of borers, but they can be broken down into three main groups.

Green timber borers

Description: These borers need a moist environment to survive, and will not re-infest dry timber. They include Pin-hole borers and the Cypress Bark weevil.

Attack: They attack live and freshly-felled trees.

Green to dry timber borers

Description: Most of the borers in this group will not re-infest the wood once it has dried out. One exception is the Auger beetle, which can continue to re-infest the wood as long as the moisture content is above 20 per cent. This group also includes such borers as the wood wasps, Longicorn and Jewel beetles.

Large Auger beetle—Bostrychopis Jusuita. Photograph courtesy of the Museum and Art Gallery of the Northern Territory

Attack: These attack live and freshly-felled trees, but complete their life cycle in dry, or drying timber. For example, if a piece of untreated green timber is used for a carved wooden figure, any larvae present continue to feed and complete their life cycle in the carving, although the time taken to complete the life cycle may be extended.

Dry timber borers

The two most common borers found damaging artefacts are the Powderpost and Furniture beetles. These borers attack dried wood. They continue to re-infest the timber until there is no sapwood left. Most attack only the sapwood because of its high starch and sugar content; but some also attack the heartwood.

Powderpost beetle. Description: Adults are 4–5mm long, cylinder-shaped and red to brown in colour. Their larval stages are not usually encountered because these remain inside the wood. After feeding, the larvae tunnel close to the surface of the wood and pupate. The adults emerge two to four weeks later through round holes which are 1–1.5mm in diameter. The dust or frass produced is like fine talcum powder when rubbed between fingers.

Attack: Powderpost beetles eat the sapwood of hardwoods.

Control: Thoroughly inspect and treat new acquisitions as necessary to prevent their introduction. Locate the source of the infestation. Arrange for the treatment of any infested artefacts by one of the low-toxic methods available: freezing, low-oxygen, controlled atmospheres. Record any damage; for example, put chalk marks on existing holes. Try to use borer-resistant timber when building.

Furniture beetle. Description: Furniture beetles are 4–6mm in length, cylinder-shaped and red/brown in colour.

Attack: Unlike the Powderpost beetle, the Furniture beetle attacks aged wood. The adults emerge through round holes about 1.5–2mm in diameter, leaving frass—like fine sand. Furniture beetles attack the sapwood of softwoods, but will infest some hardwoods.

From Northern NSW to Queensland, the Queensland Pine beetle does the same damage as the Furniture beetle.

Control: Thoroughly inspect and treat new acquisitions as necessary to prevent their introduction. Locate the source of the infestation. Arrange for the treatment of any infested artefacts using one of the low-toxic methods available: freezing, low-oxygen, controlled atmospheres. Record any existing damage: make chalk marks on existing holes; take photos. Try to use borer-resistant timber when building.

Moths

Most moths will not attack artefacts, so it is important to identify them correctly. The two most damaging moths encountered in collections are the Common clothes moth and the Casemaking clothes moth. Neither of these moths are attracted to light.

Common clothes moths

Description: Common clothes moths are 8-10mm long and are white to silver-buff in colour. The larvae are up to 12mm long and can be found amongst a network of silken tubing.

Common Clothes moth—Tineola Bisselliella—lavae (left) and adults with laval case (right). Photograph courtesy of the Museum and Art Gallery of the Northern Territory

Attack: They feed on wool, fur, hair, silk, dead insects, horn and feathers.

Control: Keep rooms light and airy. Dry-clean material where necessary before storing it in sealed plastic bags. Thorough, regular vacuuming helps to reduce the moth's food sources. Thoroughly inspect and treat new acquisitions as necessary to prevent their introduction. Locate the source of the infestation. Arrange for the treatment of any infested artefacts by one of the low-toxic methods available: freezing, low-oxygen and controlled atmospheres.

Casemaking clothes moths

Description: Casemaking clothes moths are 7–10mm long, are darker than Common clothes moths and have three dark spots on their wings. The larvae are up to 10mm long and are usually found in a case made from the material that they are feeding on. The colour of this case usually indicates what is being attacked.

Attack: They feed on wool, fur, hair, silk, dead insects, horn and feathers.

Control: Keep rooms light and airy. Dry-clean material where necessary before storing in sealed plastic bags. Thorough, regular vacuuming helps to reduce its food sources. Thoroughly inspect and treat new acquisitions as necessary to prevent their introduction. Locate the source of the infestation. Arrange for the treatment of any infested artefacts by one of the low-toxic methods available: freezing, low oxygen and controlled atmospheres.

Cases of a Casemaking clothes moth—Tinea Pellionella—found in an Aboriginal feathered bag. Photograph courtesy of the Museum and Art Gallery of the Northern Territory

Cockroaches

There are several species of cockroaches which can damage collections. Most of the damage is caused while feeding, which makes irregular surface erosion on the object. But cockroaches can also cause damage through regurgitation, leaving marks on the object they have been feeding on, or by gluing their egg cases onto objects. Cockroaches are social insects, living in groups or colonies, so it is not unusual to find hundreds in the same location.

Attack: Cockroaches eat just about anything, including leather, hair, skins, paper and books.

German cockroach (left) and Brown Banded cockroach (right). Photograph courtesy of the Museum and Art Gallery of the Northern Territory

Control: Clean regularly and thoroughly. Fill all cracks and crevices with a suitable sealant. Thorough, regular vacuuming helps to reduce its food sources. Lay cockroach baits and sticky traps where necessary. Thoroughly inspect and treat new acquisitions to prevent their introduction. Locate the source of the infestation. Arrange for the treatment of any infested artefacts by one of the low-toxic methods available: freezing, low oxygen and controlled atmospheres.

Termites

Termite damage can be extensive if left undisturbed or if not discovered. Termites are social insects, living in groups or colonies. There are many different species; the three main varieties are:

• subterranean termites. These termites travel underground from the nest to a food source. They form mud tunnels across surfaces which are exposed to air;

• dampwood termites. These are found in dead and dying trees, or wood which is in contact with damp soil. They can also be found infesting wood in poorly ventilated sub-floors. Dampwood termites rarely infest timber in well-ventilated areas; and

• drywood termites. These termites do not need ground contact because they obtain their moisture from the atmosphere or the wood that they infest. They are common in tropical and sub-tropical areas where the high humidity increases the moisture content of wood. They infest small pieces of timber, and are easily transported in artefacts such as wooden carvings.

It is recommended that you obtain information through the Forestry Commission, or from one of the many books available, about the different types of termites and how to control them.

Prevention: Many buildings are given a preventive termite treatment during construction or in subsequent years. As the pesticides used in these treatments are extremely stable, it is unlikely that further treatment will be necessary for some years after the initial treatment. This is assuming that the initial treatment was effective, and that the chemical barrier around the building has not been breached. Gardens planted near a building sometimes break the barrier, as do excavations for plumbing and extensions. Measures which reduce the risk of attack from termites include:

• not storing anything, especially wood, under buildings;

• maintaining good ventilation in sub-floor areas. This helps to prevent mould, which in turn can lead to termite attack;

• repairing any leaks; and

• using resistant and treated timbers for any structural work.

Control: Only a qualified pest controller should treat termite infestation. If the area is high-risk, a qualified person should do a regular inspection. As most termites require ground contact, removing affected material from an infested area should be sufficient to control an infestation of individual pieces. Artefacts infested with Drywood termites can be treated by one of the low-toxic methods available: freezing, low-oxygen, controlled atmospheres.

Psocids—booklice

Booklice are 1–2mm long and greyish-white in colour.

Attack: They feed mostly on mould growing on old books, or dead insects; but they can also damage the surface of materials.

Control: As booklice feed on mould, their presence usually indicates other problems: poor ventilation, for example. Look at the environment in which the material is stored and improve ventilation if necessary. Thoroughly inspect and treat new acquisitions to prevent their introduction. Locate the source of the infestation. Arrange for the treatment of any infested artefacts by one of the low-toxic methods available: freezing, low oxygen and controlled atmospheres.

Silverfish

Silverfish are 5–15mm long and silver-grey in colour. They have three distinct tails. Young silverfish resemble adults.

Attack: Silverfish feed on paper, fabrics, especially starched or stained material, cotton, linen, photos, book bindings and paste or sizing. Their damage includes holes and surface erosion.

Control: Increased ventilation and regular vacuuming will help to make the environment less desirable to this pest. Wrap material in acid-free tissue and seal in plastic bags. Thoroughly inspect and treat new acquisitions to prevent their introduction. Locate and treat the source or sources of infestation. Treat any infested artefacts by one of the low-toxic methods available: freezing, low-oxygen, controlled atmospheres.

Rodents

Rats and mice can cause extensive damage to collections through feeding—gnawing on materials—and through staining from their droppings. Their nests can also be a source for insect infestations.

Control: Seal possible entry points. Removing food sources and repairing any leaking pipes helps to deter rodents. Avoid baiting because the rodent may die somewhere where you are unable to find the body, causing unpleasant odours as well as insect problems. Use traps if necessary.

Birds

Bird droppings can damage collections; their nests can also cause insect problems.

Control: Many different methods of deterring birds are available. These methods include:

• using chicken wire to keep them out of roof and wall cavities;

• placing deterrents such as plastic or wire strips on landing surfaces; and

• increasing the angle of the ledge to remove roosting sites.